Urban development and increasing the population and industrial activity and consumption of fossil fuel

induce pollution seriously. Those effects in short time cause various diseases and in long time cause climatic

and environmental changes such as comfortable climate duration. In this research, fifty years of climatic

data (1957-2006) such as temperature and relative humidity in Yazd station were used. Mahani climatic

conformability model determined the suitable months for human physiological comfortability in five

ten-years old period. Also linear procedure of its change is forecasted up to 2016.

The results showed the temperature trend in Yazd Station is hot and most of the months, the temperature

have a hot trend, however expectation for future comfortable months for human physiology is cold

months of year and in warm months of year the heat stresses will increase.